In a televised meeting with security officials, Putin detailed proposed changes to the country's nuclear doctrine, adding new criteria for launching a nuclear response.

"We see the modern military and political situation is dynamically changing and we must take this into consideration," Putin said, citing "the emergence of new sources of military threats and risks for Russia and our allies".

Putin outlined a potential update, saying that "it is proposed to consider aggression against Russia by any non-nuclear state, but with the participation or support of a nuclear power, as their joint attack on Russia".

This would seemingly apply to Ukraine, a non-nuclear state that receives military support from the United States and other nuclear-armed countries.

Putin also said that proposed changes "clearly set the conditions for Russia to transition to using nuclear weapons".

"We will consider such a possibility once we receive reliable information about a massive launch of air and space attack weapons and their crossing our state border," the president added.

"I mean aeroplanes of strategic and tactical aviation, cruise missiles, drones, hypersonic and other aircraft," Putin said.

The president said the proposed changes also meant "we reserve the right to use nuclear weapons in case of aggression against Russia and Belarus", Moscow's close ally.

He added that this included a situation in which another state "using ordinary weapons, creates a critical threat to our sovereignty".

The president said that Russia's nuclear weapons were "the most important guarantee of security of our state and its citizens".

"It's important to predict how the situation will develop and accordingly adapt the clauses of the document on strategic planning to current realities," Putin said.